How to drill a nightrider 36 rim?

Hey guys, figured I'd ask people who know more than me about this before
actually doing something (and besides I'm a few thousand kms from my 36
with this rim on anyhow..).

I heard from Sam W (redwelly) that drilling the inside of his
nightrider rim out only saved about 50 odd grams (compared to airfoils
which dropped much more - thinner inner wall metal on the nightriders
apparently). Since riding his wheel with shaven tire, 29'er tube, ss
spokes and drilled rim, I really want a similar setup. The weight
savings is ridiculous - and when I get a schlumpf for it - mm!

He was saying that the metal is much thinner on the inner wall, which
makes me wonder - how dangerous/unwise would it be to drill out the
outer wall of the rim a la 19" trials gear that's going around right
now? I'm a road weenie as is, so strength isn't a super huge deal to me
unless the wheel is flopping every which way and running into my brakes,
so if it would hold up to road riding I'd be all for it.

My question is, what would happen? It would really suck if building the
wheel back up caused the rim to die in weird ways, but it also seems
like the weight savings would be worth it, especially if it was on the
order of 100+ grams at the extremity of the wheel.

And besides, I might try it anyways and risk having to buy a second rim
to mess up, who knows?

I was thinking the same thing but don't have the rim to drill out yet.
I think it would be safe as long as you keep it for road use. When I
have disposable income again I plan to build up a super light geared
36er for pure road riding.

If there are vertical walls between the inner and outer walls you would
want to make sure that you keep those intact and the rim should be fine.

flyer wrote:
Since riding his wheel with shaven tire, 29'er tube, ss spokes and
drilled rim, I really want a similar setup.

And when you tried it, it even had a 36" tube in (after my 29er blew
out before the marathon). It should have been lighter than that!

Sadly the shaven tyre thing means it doesn't last very long - I think
the compound is a bit softer than the TA, and mine is showing threads
at several places (not just turning spots aligned with the cranks
either), after cutting it down to about 1mm of groove depth and then
riding it about 1600km. Now it's going to be kept as my racing/record
breaking tyre and I'll go back to another one for everyday use.

On my rim I drilled three 1/2 inch (yes, randomly imperial drill bits)
holes between each spoke, and enlarged the spoke access holes to the
same 1/2 inch size. I also did 4.5mm holes in each 'corner' of the big
holes - running in two rows around the sides of the inner surface. That
was a lot more work for a lot less benefit than the big holes, but looks
quite cool. The whole thing took three hours with a pillar drill (in a
physics workshop at my university), and I finished with a Nightrider
Pro weighing 1069g.

Yeah, I'm tempted to drill the outside (visible) surface as well and
see what happens. When I get home from work I'll find photos of what I
have done so far to the inside of my rim.

I was planning to do it. But remember that it is the rim that has most
to say when building a strong wheel. A heavier rim means a stiffer
wheel in most cases. I was spoking up the new nightrider rim but I
thougt the rim was to soft for me. I do mostly Coker Muni. Havent tried
the nightrider rim, but when building the wheel I realy can feel the
airfoil is a lot stiffer. That bacause of a deeper cross section rim is
a lot stiffer than a ordinary cross section rim. But I guess a drilled
rim works if you mainly spin on the flat.

The outside edge of the small holes was just starting to cut into a
vertical part inside the profile of the rim extrusion, so I think
that's about as wide as you can go with drilling holes across the
surface.

I'd definitely recommend using a pillar drill for this as you need the
height control to not go too far and get the second surface by
accident.

I didn't weigh my actual rim beforehand, but going by the stated weight
of 1116g, and my measured 'after' weight of 1069, I saved 47g.
(Ironically I threw away 20g of that by building it up with brass
nipples - it'll be blingbling gold alloys next time)

EDIT: Sam: Did you have to use special rim tape after you drilled the
rim?

Nope. Maybe I should have, but I just used 'normal' hockey tape.
Apprently it is lighter than other rim tapes, but it is also absorbant
so gets heavier if it's wet! The pattern of holes is narrow enough to
allow decent enough coverage with one loop of tape - again, saving
weight. I guessed that each circumference of tape is about 20g, so you
don't want to do two unless you really need to.

I've taken the tyre off several times now, and the tape is getting
quite peeled back in places, but I've had no problems with it so far.
All the holes have a chamfered edge so they aren't sharp.